add swift_task_checkIsolatedImpl to CooperativeGlobalExecutor

Author: ktoso

stdlib/public/Concurrency/CooperativeGlobalExecutor.inc

@@ -18,6 +18,7 @@
 ///   swift_task_enqueueGlobalImpl
 ///   swift_task_enqueueGlobalWithDelayImpl
 ///   swift_task_enqueueMainExecutorImpl
+///   swift_task_checkIsolatedImpl
 /// as well as any cooperative-executor-specific functions in the runtime.
 ///
 ///===------------------------------------------------------------------===///
@@ -257,3 +258,10 @@ swift_task_donateThreadToGlobalExecutorUntil(bool (*condition)(void *),
     swift_job_run(job, SerialExecutorRef::generic());
   }
 }
+
+SWIFT_CC(swift)
+static void swift_task_checkIsolatedImpl(SerialExecutorRef executor) {
+  _task_serialExecutor_checkIsolated(
+      executor.getIdentity(), swift_getObjectType(executor.getIdentity()),
+      executor.getSerialExecutorWitnessTable());
+}